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See detailVégetation aquatique et supra-aquatique des cours d'eau luxembourgeois
Sossey Alaoui, Khadija ULg

Book published by PRESSES ACADÉMIQUES FRANCOPHONES (2015)

La répartition des Macrophytes aquatiques (Phanérogames et Bryophytes) a été étudiée sur l’ensemble des cours d’eau luxembourgeois. Des prospections macrophytiques ont été réalisées pour 340 stations ... [more ▼]

La répartition des Macrophytes aquatiques (Phanérogames et Bryophytes) a été étudiée sur l’ensemble des cours d’eau luxembourgeois. Des prospections macrophytiques ont été réalisées pour 340 stations entre 2000 et 2003. Dans chacune d’entre elles, des paramètres mésologiques ont été mesurés et des analyses physico-chimiques des eaux ont été effectuées dans 63% des stations. La relation macrophytes-habitat a été envisagée selon deux approches : multidimensionnelle d’une part et par des profils écologiques d’autre part. Les principales espèces aquatiques et semi-aquatiques des rivières luxembourgeoises ont été classées en différents groupes par une Analyse Factorielle Multiple (AFM) sur base des descripteurs physico-chimiques et morpho-métriques impliqués dans la dispersion, l’établissement et la persistance des espèces aquatiques. Basée sur l’abondance de ces groupements, une typologie floristique des cours d’eau a conduit à l’individualisation de différents groupes de stations : 1 les têtes de bassins ardennais caractérisées par Chiloscyphus pallescens et C. polyanthos ainsi que par un éclairement faible et un substrat grossier ; 2 les cours principaux de l’Oesling à Ranunculus penicillatus, R. peltatus ; 3 Berula erecta et Veronica beccabunga caractérisent les zones amonts du Gutland dont les eaux montrent des teneurs élevées en nitrates ; 4 les cours principaux lorrains dont les eaux sont plus minéralisés et riches en SO42- sont caractérisés par P. crispus, E. canadensis, P. natans et Z. palustris ; 5 et finalement les zones fortement eutrophisées (rithrons) caractérisées par un grand nombre d’espèces (Potamogeton pectinatus, P. perfoliatus, Sparganium emersum….) et par des critères morpho-métriques très importants (profondeur, éclairement, largeur et température). Des profils écologiques et des cartes de distributions des principales espèces rencontrées (Phanérogames et Bryophytes) nous ont permis de délimiter leurs comportements vis a vis de l’eutrophisation et de la minéralisation. Les différences observées par rapport à la littérature témoignent d’une prolifération des espèces polluo-tolérantes d’une part et d’une pression anthropique importante le long du réseau hydrographique luxembourgeois d’autre part. Une méthode indicielle a été appliquée afin d’évaluer la qualité des rivières sur base des espèces inventoriées. Néanmoins, la faible occurrence des espèces et la non prise en compte des algues ont diminué l’acuité de la méthode. L’importance des formations végétales riveraines au sein des écosystèmes aquatiques et plus particulièrement dans le domaine de la bioindication a été étudiée également. Le pouvoir bioindicateur pour les facteurs acidité, azote, humidité, et lumière (ELLENBERG et al., 1992) a été précisé pour 220 espèces rivulaires inventoriées le long des sites de l’Oesling et du Gutland. Une typologie des biotopes riverains a été dégagée sur base de ces valeurs bioindicatrices. Le déterminisme de la richesse des sols riverains a été envisagé dans sa composante naturelle Oesling-Gutland, ainsi que dans sa composante anthropique. [less ▲]

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See detailDe l’ordre répressif étatique à celui de la Cour pénale internationale : la sensibilité du juge de Strasbourg à la gravité des faits en cause
Deprez, Christophe ULg

Conference (2015, May 29)

Cette présentation PowerPoint a servi de support à une communication orale dans le cadre de l'édition 2015 de la Conférence des Assistants en droit de Belgique (ACCA), organisée le 29 mai 2015 par l ... [more ▼]

Cette présentation PowerPoint a servi de support à une communication orale dans le cadre de l'édition 2015 de la Conférence des Assistants en droit de Belgique (ACCA), organisée le 29 mai 2015 par l'Université catholique de Louvain. [less ▲]

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See detailApproche processuelle de la dépression : Impact de processus psychologiques l'activation ou l'évitement en fonction du sexe
Wagener, Aurélie ULg

Conference (2015, May 29)

La dépression est caractérisée par des symptômes affectifs, cognitifs et somatiques. Elle est également caractérisée par une diminution du niveau d’engagement dans des activités ce qui peut être ... [more ▼]

La dépression est caractérisée par des symptômes affectifs, cognitifs et somatiques. Elle est également caractérisée par une diminution du niveau d’engagement dans des activités ce qui peut être conceptualisé comme de l’évitement comportemental (symptôme comportemental). Il est en effet fréquent que les patients dépressifs s’engagent de moins en moins dans des activités qui leur plaisaient auparavant (voir des amis, etc.) Ce faible niveau d’activités maintient leur humeur dépressive. Cette relation entre dépression et faible niveau d’engagement dans des activités est bien établie dans la littérature scientifique mais les relations entre les processus cognitifs sous-jacents sont encore mal connues. Selon les modèles théoriques de la dépression (Beck, 2008; Lewinsohn, 1985; Watkins, 2009), cinq types de processus psychologiques (PP) sont impliqués dans la symptomatologie dépressive : les pensées négatives répétitives, les stratégies de régulation émotionnelle non-adaptées, un faible niveau de satisfaction environnementale, une image de soi négative et une tendance à l’inhibition. Nous faisons l’hypothèse que ces PP pourraient être les facteurs explicatifs de l’évitement comportemental. Par ailleurs, nous faisons également l’hypothèse que d’autres PP pourraient être considérés comme des facteurs explicatifs de l’activation comportementale : les stratégies de régulation émotionnelle adaptées, un haut niveau de satisfaction environnementale, une image de soi positive, une tendance à l’approche et un concept de soi clair. Ces PP consisteraient en des facteurs protecteurs de la dépression. Dès lors, notre objectif est d’évaluer les liens entre évitement comportemental, activation comportementale et PP. Pour ce faire, en nous basant sur le modèle de Kinderman (2013), nous avons élaboré un modèle conceptualisant l’influence que peuvent avoir les PP précités sur, d’une part, l’évitement comportemental et, d’autre part, l’activation comportementale. De plus, l’étude évalue l’adéquation de ce modèle de façon à comparer les hommes et les femmes. 477 adultes issus de populations cliniques et non-cliniques (119 hommes, 358 femmes, âge moyen = 34,25, ET = 11,85) ont complété une étude en ligne évaluant les PP (pensées négatives répétitives, stratégies de régulation émotionnelles, satisfaction environnementale, image de soi, tendance à l’inhibition/l’approche, clarté du concept de soi), l’évitement comportemental et l’activation comportementale. Différents questionnaires évaluaient chacun de ces PP. Dès lors, des scores factoriels ont été réalisés pour représenter chaque PP. Les résultats préliminaires issus d’analyses factorielles confirmatoires semblent révéler des différences entre les hommes et les femmes. Pour les hommes, une image de soi négative, des stratégies de régulation émotionnelle non-adaptées et un faible niveau de satisfaction environnementale sont liés à l’évitement comportemental alors qu’un haut niveau de satisfaction environnementale et une image de soi positive sont liés à l’activation comportementale. Pour les femmes, un faible niveau de satisfaction environnementale, des stratégies de régulation émotionnelle non-adaptées et des pensées négatives répétitives sont liées à l’évitement comportemental alors qu’un haut niveau de satisfaction environnemental et une image de soi positive sont liées à l’activation comportementale. La collecte des données étant toujours en cours, les résultats globaux seront présentés durant le congrès. Les implications cliniques de ces résultats seront discutées telles que la pertinence de travailler sur le niveau de satisfaction environnementale. [less ▲]

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See detailStone tool hafting and use in the European Upper Palaeolithic: the first results of the analysis of Gravettian tools from Hohle Fels
Taipale, Noora ULg; Rots, Veerle ULg

Conference (2015, May 28)

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, while extensive studies that would utilise the full potential of microwear analysis ... [more ▼]

European Upper Palaeolithic lithic assemblages have been so far defined largely on a typological or technological basis, while extensive studies that would utilise the full potential of microwear analysis have been few. This contribution presents the first results of an ongoing PhD project dedicated to the variability in stone tool use and hafting in the Upper Palaeolithic of Central and Western Europe. The aim of the project is to understand the development as well as regional patterns in tool hafting and use in the Gravettian and Magdalenian, and thus better explain the observed morphological and technological shifts. For this purpose, samples of tools from five European key sites with well-dated sequences (Hohle Fels, Geißenklösterle, Vogelherd, Maisières-Canal, and Abri Pataud) will be analysed giving a special emphasis on hafting traces. The study wishes to promote functional analysis as an integral part of technological studies, not as a mere side note. The German cave site Hohle Fels is used here as a case study to illustrate the potential of this kind of approach. The first results of the analysis of the site’s Gravettian material will be put into a wider context of earlier published results as well as preliminary observations made on the other assemblages included in the present study. Building on these results, the impact of tool hafting and use on the morphology of Gravettian lithic implements will be discussed. [less ▲]

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See detailTool use and hafting in the Middle Palaeolithic of Northern Africa An on-going use-wear analysis on the Mousterian/Aterian assemblages of Ifri n’Ammar (Morocco)
Tomasso, Sonja ULg; Rots, Veerle ULg

Conference (2015, May 28)

The so-called “Aterian Culture” has received attention since the early days of prehistoric archaeology in Northern Africa. Several definitions were proposed, which triggered a debate around this cultural ... [more ▼]

The so-called “Aterian Culture” has received attention since the early days of prehistoric archaeology in Northern Africa. Several definitions were proposed, which triggered a debate around this cultural concept. In particular the presence of the tanged tools was a crucial element in these debates and the tangs were considered to potentially represent the earliest indications of hafting, or at least of intentional morphological adaptations in view of hafting. In contrast to numerous typological and technological studies of Aterian and Mousterian assemblages, use-wear analyses have been scarce up until today. However, for a better understanding of several aspects of these Middle Palaeolithic “cultures”, functional data needs to be taken into consideration. Given the issue of tanged pieces, the potential of such detailed studies on production, hafting and use is high. In this paper, the first results will be presented of an on-going use-wear analysis on tools from the Aterian/Mousterian assemblages of Ifri n’Ammar. This rock shelter presents an ideal case thanks to its particularly rich and well preserved stratigraphy. Around 200 artefacts have been selected up to now, based on their degree of preservation and without restrictions on the level of the tool types. Artefacts were examined macroscopically and microscopically in a search for evidence of their production, hafting and use and an experimental program was set up. Archaeological interpretations are based on new experiments, as well as on the existing large experimental reference collection available at TraceoLab at the University of Liège. The long-term goal of the study is to use a functional approach to answer questions related to lithic assemblage variability. At Ifri n’Ammar, it is clear that the tangs occur on a variety of tools. Due to the presence of tangs in the Aterian and their absence in the Mousterian, it can be hypothesized that there was a shift in hafting techniques between the two cultures/periods. In order to understand whether this change was triggered by functional, cultural, or environmental factors, more functional data is clearly needed. [less ▲]

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See detailParental and romantic attachments in teen datings : different meanings in boys' and girls' intimacy
Courtain, Audrey ULg; Lepas, Jennifer; Boulard, Aurore ULg et al

Poster (2015, May 28)

First proposing a relational understanding of the child’s very first years, attachment theory has since then been taken into consideration in friendships and romantic relationships. Indeed, the internal ... [more ▼]

First proposing a relational understanding of the child’s very first years, attachment theory has since then been taken into consideration in friendships and romantic relationships. Indeed, the internal working models (IWM) built upon early interactions are to be used on and on in many other situations as guidelines to understand what is going on for the self, this particular other and their specific relationship. Different attachment styles are thus likely to develop: secure or insecure (anxious/preoccupied, avoidant/dismissive, fearful). Considering teen dating, attachment is deeply involved, especially for two reasons: first, a certain questioning, but also re-actualization, of the attachment to parents; second, a new kind of attachment, meaning the one to the romantic partner. These elements lead us to test hypotheses linking attachment to parents and attachment to romantic partners, but also linking these attachments to some teen dating characteristics, such as the age when first dating, the number of love relationships, the longest-lasting love relationship and the fear of intimacy. Our hypothesis was tested among 283 teenagers (mean age = 17.43) with two self-administered questionnaires (the Behavioral Systems Questionnaire and the Fear of Intimacy Scale). Our statistical analyses were made of Pearson Chi², Anova and Post-Hoc Fisher (LSD). We see three types of interesting results. First, there is a significant relationship between attachment (parental and romantic attachments) and the number of love relationships and the fear of intimacy. Second, these relationships are differently established once considered the attachment modalities. Third, gender differences appear, girls looking more influenced by their attachment style than boys. [less ▲]

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See detailThe more you know...........various approaches in the analysis of tools from Liang Bua, Flores Indonesia
Lentfer, Carol ULg; Stephenson, Birgitta; Cnuts, Dries ULg et al

Conference (2015, May 28)

Chipped stone flakes from sedimentary deposits from the Liang Bua site, Flores, Indonesia have been found in association with faunal remains and skeletal remains identified as Homo floresiensis. Use-wear ... [more ▼]

Chipped stone flakes from sedimentary deposits from the Liang Bua site, Flores, Indonesia have been found in association with faunal remains and skeletal remains identified as Homo floresiensis. Use-wear and well-preserved organic residues on these flakes provide an opportunity to understand subsistence and behaviour of Homo floresiensis by determining how they were manipulated and what they were used for. This paper describes the analytical techniques including various microscope and staining methodologies used in residue analyses. It compares the efficacy and describes the outcome of these techniques in relation to the functional analysis of the Liang Bua lithic assemblage. [less ▲]

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See detailHeterogeneity of multitasking abilities in schizophrenia.
Laloyaux, Julien ULg; Van der Linden, Martial ULg; Laroi, Frank ULg

Conference (2015, May 28)

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to ... [more ▼]

Difficulties in everyday life activities are core features of persons diagnosed with schizophrenia, and in particular for those activities requiring multitasking capacities. Multitasking refers to activities (e.g. preparing a meal) where the person has to: (a) carry out and alternate between different tasks that vary in terms of priority, difficulty and duration; (b) define the tasks’ targets; (c) and face unexpected problems during the realization of these tasks. Moreover, schizophrenia is characterized by a great heterogeneity in regard to their everyday life difficulties and cognitive functioning. At present, patients’ multitasking capacities have not been adequately examined in the literature due to an absence of suitable assessment strategies. We thus recently developed a computerized real-life activity task designed to take into account the complex and multitasking nature of certain everyday life activities where participants are required to prepare a room for a meeting (i.e. the Computerized Meeting Preparation Task, CMPT). The aim of this study was to examine the multitasking abilities in persons diagnosed with schizophrenia and in particular the existence of subgroups of patients in regard to their performances on cognitive measures and on the CMPT. Sixty-two patients diagnosed with schizophrenia and 39 paired healthy controls completed the CMPT and a cognitive battery. The results reveal that the CMPT possesses good sensitivity and suggest three underlying constructs of multitasking (Memory, Planning and Intent), which were found to be underpinned by several cognitive functions and multitasking aspects. Moreover, cluster analyses revealed subgroups of patients differing in terms of their cognitive and CMPT performances. Taken together, these results show the need for a cognitive model of multitasking abilities in persons diagnosed with schiozphrenia. Taken together, this cognitive model and the CMPT, could be a good basis for cognitive interventions of multitasking abilities in schizophrenia. Finally, the results underline the heterogeneity of schizophrenia. [less ▲]

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See detailAn ALE meta-analysis on the neural correlates of personal goal processing during episodic future thoughts and mind-wandering
Stawarczyk, David ULg; D'Argembeau, Arnaud ULg

Conference (2015, May 28)

The ability to project oneself into the future is a multi-determined mental faculty that depends on various cognitive processes supported by an extended set of brain regions. The aim of the present study ... [more ▼]

The ability to project oneself into the future is a multi-determined mental faculty that depends on various cognitive processes supported by an extended set of brain regions. The aim of the present study was to examine a crucial component of future thinking—personal goal processing—and to determine its neural correlates during both experimentally directed mental time travel towards the future and mind-wandering, a form of spontaneous thoughts characterized by a prospective bias towards upcoming events. To address this question, we performed three distinct ALE meta-analyses of brain imaging studies on episodic future thinking, mind-wandering, and personal goal processing. We then examined the commonalities and differences in brain activity between these three areas of research. The results showed that the three domains activated a common set of brain regions within the default network including the posterior inferior parietal cortex, posterior cingulate cortex, lateral temporal lobe, and, most notably, the medial prefrontal cortex. Differences in activation were also observed, and the medial prefrontal cortex was more activated during personal goal processing than the other two domains. These findings suggest that the medial prefrontal cortex mediates the processing of personal goals during both episodic future thinking and mind-wandering. [less ▲]

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See detailThe hot Jupiter WASP-­121 b: A planet heading towards its doom
Delrez, Laetitia ULg

Conference (2015, May 28)

We present here the discovery by the WASP-South survey, in close collaboration with the Euler and TRAPPIST telescopes, of WASP-121 b, a new remarkable short-period transiting hot Jupiter. WASP-121 b is a ... [more ▼]

We present here the discovery by the WASP-South survey, in close collaboration with the Euler and TRAPPIST telescopes, of WASP-121 b, a new remarkable short-period transiting hot Jupiter. WASP-121 b is a very inflated (1.86 Rjup) Jupiter-mass (1.18 Mjup) planet that transits every 1.27 days a bright active F6V star. A notable property of WASP-121b is that its orbital semi-major axis is only 15% larger than its Roche limit, which suggests that the planet might be close to tidal disruption. Furthermore, its large size and extreme irradiation (7.1 10^9 erg s^-1 cm^-2) make it an excellent target for atmospheric studies via secondary eclipse observations. Using the TRAPPIST robotic telescope, we indeed detect its thermal emission in the z’-band at better than ~4sigma, the measured occultation depth being 603+-130 ppm. This measurement is a first for a ground-based 60cm telescope. Finally, from a measurement of the Rossiter-McLaughlin effect with the CORALIE spectrograph, we infer a sky-projected spin-orbit angle of 257.8+-6 deg. This result indicates a significant misalignment between the spin axis of the host star and the orbital plane of the planet, the planet being in a nearly polar orbit. [less ▲]

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See detailFully automated electrophoretically mediated microanalysis system for CYP1A1 activity monitoring
Farcas, Elena ULg; Servais, Anne-Catherine ULg; Lamalle, Caroline ULg et al

Conference (2015, May 28)

In order to evaluate the potentiality of capillary electrophoresis for CYP1A1 activity monitoring, an in-line method was developed with the well-known 7-ethoxycoumarin substrate. The electrophoretically ... [more ▼]

In order to evaluate the potentiality of capillary electrophoresis for CYP1A1 activity monitoring, an in-line method was developed with the well-known 7-ethoxycoumarin substrate. The electrophoretically mediated microanalysis approach was used with CYP1A1 supersomes to provide a rapid and fully automated method. The in-line homogenous enzyme assay was performed in physiological conditions (pH 7.4), whereas a MEKC buffer was used as background electrolyte. In order to reduce the analysis time, the short end injection was performed. Firstly a plug containing CYP1A1 supersomes was hydrodynamically injected into a fused silica capillary, followed by a plug of co-factor (NADPH) and substrate (7-ethoxycoumarin) and finally another plug of CYP1A1 (sandwich mode). The experimental conditions were finely investigated and tuned by design of experiment methodology. The metabolization rate measured in the optimized conditions was comparable with the one obtained after off-line metabolization. Finally, inhibition studies were conducted and a significant decrease of 7-hydroxycoumarin formation was observed using apigenin as CYP1A1 potent inhibitor. [less ▲]

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See detailQuelle marge de manœuvre pour l'Amérique latine face à la concurrence stratégique entre la Chine et l’Union européenne?
Wintgens, Sophie ULg

Scientific conference (2015, May 28)

Cet article interroge la marge de manœuvre conférée à l’Amérique latine par la concurrence stratégique entre la Chine et l’Union européenne, devenues deux importants partenaires extrarégionaux d’un sous ... [more ▼]

Cet article interroge la marge de manœuvre conférée à l’Amérique latine par la concurrence stratégique entre la Chine et l’Union européenne, devenues deux importants partenaires extrarégionaux d’un sous-continent traditionnellement tourné vers les États-Unis. [less ▲]

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See detailThe neural bases of proactive and reactive control processes in healthy aging
Manard, Marine ULg; François, Sarah ULg; SALMON, Eric ULg et al

Poster (2015, May 28)

Background. Research on cognitive control suggests an age-related decline in proactive control abilities (an anticipatory form of control) whereas reactive control (consecutive to conflict detection ... [more ▼]

Background. Research on cognitive control suggests an age-related decline in proactive control abilities (an anticipatory form of control) whereas reactive control (consecutive to conflict detection) seems to remain intact [1]. As proactive and reactive control abilities were associated to specific brain networks [2], this study investigated age-related effects on the neural substrates associated to each kind of control. Method. A modified form of the Stroop task was administered to 16 young and 16 older adults in an event-related fMRI experiment. In this version of the Stroop task, three different contexts were created: (1) a mostly congruent context (MC, inducing reactive control) with a majority of congruent items, (2) a mostly incongruent context (MI, inducing proactive control) with mainly interfering items, (3) a neutral context (MN) with mainly neutral items. Preprocessing and statistical analyses were performed with SPM8 (p<.001 uncorrected). Results. Behavioral results (p<0.05) indicated faster processing of interferent items in the MI than MC context in young participants only. With regard to neuroimaging data, the comparison of the two groups showed that the processing of interferent items in the MI context is associated to decreased activity in (mainly right-sided) frontal and temporal areas in the older group. On the contrary, in the MC context, increased activity was observed in bilateral frontal areas for older compared to younger participants. Discussion. Behavioral results confirm that older participants have difficulties with the implementation of proactive control that is associated to decreased brain activity (compared to young participants) in areas underlying Stroop performance. However, the recruitment of supplementary frontal areas we observed in the reactive control condition suggests compensation processes. So, aging seems to differentially affect the neural networks associated to the various kinds of cognitive control. [less ▲]

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See detailThe impact of ageing on episodic memory encoding: an fMRI study
François, Sarah ULg; Angel, Lucie; Salmon, Eric ULg et al

Poster (2015, May 28)

It is now commonly accepted that a decline in episodic memory is observed with ageing: while recollection processes are impaired, familiarity seems to be relatively preserved (a). Older individuals appear ... [more ▼]

It is now commonly accepted that a decline in episodic memory is observed with ageing: while recollection processes are impaired, familiarity seems to be relatively preserved (a). Older individuals appear to recruit prefrontal areas bilaterally when their encoding is successful, while in young adults this activation is found to be left-lateralized (b). In this study, we were interested in the differences between younger and older participant regarding cerebral activity during encoding depending on whether the item elicited recollection or familiarity during the recognition phase. Twenty young volunteers (aged 19 to 29 years old) and 19 older volunteers (aged 60 to 78 years old) were presented visual stimuli depicting objects. During a first fMRI session, they were asked to make a size judgement about them. Then, in a second phase, the subjects were shown the items previously encountered during the encoding phase, as well as distractors. Participants' task was to determine which one were new and which one were seen earlier. For the latter, they also performed a Remember-Know judgement. Data were analysed using SPM8, with an event design comparing modifications in cerebral activity between the two subjects groups during encoding (1) for the items leading to recollection during the recognition phase compared to those leading to familiarity, and (2) for the items associated with familiarity during the recognition phase compared to those which were not recognized. Results show that older adults display a heightened activity in the right middle frontal gyrus, medial cingulate and paracingulate left gyri as well as in the precuneus, bilaterally when they engage recollection processes. Given that activations in these areas did not correlate with performance, they could be interepreted either as dedifferentiation or as an attempt of the ageing brain to compensate for a less elaborate encoding. However, no increase of activity was associated with familiarity processes in older adults, possibly because they are less demanding regarding attentional resources. (a) Bugaiska, A., Clarys, D., Jarry, C., Taconnat, L., Tapia, G., Vanneste, S., & Isingrini, M. (2007). The effect of aging in recollective experience: the processing speed and executive functioning hypothesis. Consciousness and Cognition, 16(4), 797-808. doi: 10.1016/j.concog.2006.11.007 (b) Duverne, S., Motamedinia, S., & Rugg, M. D. (2009). The relationship between aging, performance, and the neural correlates of successful memory encoding. Cerebral Cortex, 19(3), 733-744. doi:10.1093/cercor/bhn122 [less ▲]

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See detailThe effect of ageing and encoding instructions on episodic memory
Hagelstein, Catherine ULg; François, Sarah ULg; Manard, Marine ULg et al

Poster (2015, May 28)

During ageing, a decline in episodic memory is observed, characterized by decreased recollection (a). In this study, we investigated the influence of encoding instructions, intentional or incidental, on ... [more ▼]

During ageing, a decline in episodic memory is observed, characterized by decreased recollection (a). In this study, we investigated the influence of encoding instructions, intentional or incidental, on the performance of younger and older adults during an episodic memory task. Twenty young volunteers (aged 18 to 30 years old) and 20 older volunteers (aged 61 to 72 years old) participated in this experiment. The stimuli consisted of 300 black-and-white drawings of common objects. The task comprised two steps. During the encoding phase, 100 items were presented once ("hard" condition) and 100 other items were presented twice ("easy" condition). During recognition, the items from the encoding phase were presented again, as well as 100 new items. In each age group, half of the participants received incidental encoding instructions (they had to make size judgements about the objects depicted) while the other half were explicitly asked to memorize the objects presented because they would be asked to recognize them later on (intentional encoding). During recognition, they performed a Remember-Know judgement for the items they believed they had seen earlier. We carried out ANOVAs in order to test for the influence of instructions, age group and number of repetitions of the items in one hand on the percentage of recollection and on the other hand on the percentage of familiarity (p<.05). Results show a significant effect of age, with more correct recollection responses in young adults, whereas more correct familiarity was found in older adults. Furthermore, it was found that the items presented twice lead to more recollection than those presented only once. Finally, these results also suggest that in the older group of participants, only for the items presented twice, intentional encoding instructions lead to more recollection and less familiarity. This finding is consistent with previous work showing that the elderly do not easily use elaborate encoding strategies, and that they need more support (here, a second exposition to the material) in order to perform a deep encoding when they are encouraged to do so with intentional learning instructions (b). (a) Bugaiska, A., Clarys, D., Jarry, C., Taconnat, L., Tapia, G., Vanneste, S., & Isingrini, M. (2007). The effect of aging in recollective experience: the processing speed and executive functioning hypothesis. Consciousness and Cognition, 16(4), 797-808. doi: 10.1016/j.concog.2006.11.007 (b) Froger, C., Bouazzaoui, B., Isingrini, M., & Taconnat, L. (2012). Study time allocation deficit of older adults: the role of environmental support at encoding? Psychology and Aging, 27(3), 577-588. doi:10.1037/a0026358 [less ▲]

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